The present disclosure relates generally to an imaging module mountable inside an imaging reader for reading targets, such as bar code symbols, to be electro-optically read by image capture over a field of view, and, more particularly, to supporting a plurality of printed circuit boards on which electro-optical reading and/or interfacing components are mounted to lie in predetermined planes in a predetermined angular relationship on the module, and, still more particularly, to a method of assembling the module, and of mounting the assembled module as a unitary assembly in the reader.
Solid-state imaging readers have long been used, in both handheld and hands-free modes of operation, in many industries, such as retail, manufacturing, warehousing, distribution, postal, transportation, logistics, etc., to electro-optically read targets, such as one- or two-dimensional bar code symbols to be decoded. A known imaging reader generally includes an imaging module, also known as a scan engine, mountable in the reader and having a chassis on which an engine printed circuit board (PCB) is mounted. A solid-state imager for capturing an image of a target along an imaging axis over a field of view is mounted on the engine PCB. For optical reasons, it is desirable for the imager to directly face the target with its imaging axis generally horizontal, and to lie in a generally upright or vertical plane, to thereby maximize imaging performance since lying in any other plane could tend to defocus the captured image. Typically, an aiming light source, which directs one or more visible aiming lights along respective aiming axes to the target to visually locate the target, is also mounted on the engine PCB, and an illuminating light source, which emits one or more illuminating lights along respective illuminating axes toward the target to illuminate the target, especially in dimly lit environments, is mounted either on the engine PCB, or somewhere else on the chassis. For optical reasons, it is also desirable for the aiming light source and/or the illuminating light source to directly face the target with their respective aiming and/or illuminating axes generally horizontal, and to lie in a generally upright or vertical plane, to thereby maximize the amount of aiming and/or illuminating light that is directed to the target, and to avoid excessive light corrections with aiming and/or illuminating lenses. When the imager, the aiming light source and/or the illuminating light source are all surface-mounted on the same engine PCB such that their imaging, aiming and/or illuminating axes are generally perpendicular to the engine PCB, then the engine PCB is typically supported on the chassis to lie in the generally upright or vertical plane.
It is known to configure the handheld imaging reader with a generally gun-shaped configuration having a handle that, for ergonomic reasons, extends along a handle axis that is typically tilted at a tilt angle of around fifteen to about twenty-two degrees with respect to the vertical. Rather than not occupy and waste the available space inside the handle, another PCB, also known as a handle or control or decode PCB, is mounted inside, and extends along the handle axis of, the handle. The handle PCB advantageously supports other electro-optical reading components, such as a controller or processor for controlling the imager, the aiming light source and the illuminating light source, and for processing the captured image. The handle PCB also supports an electrical interface connector at a lower end of the handle PCB adjacent a bottom of the handle, for connection to electrical power/data cables, as well as an indicating light source at an upper end of the handle PCB adjacent a top of the handle for visually indicating when a successful reading of the target has been performed. The handle PCB is mounted at the tilt angle relative to the engine PCB by using separate mounting brackets or frames that are individually secured in place to the chassis.
Although generally satisfactory for their intended purpose, the mounting brackets that are used to hold the engine PCB and the handle PCB at the tilt angle are relatively cumbersome to mount on the chassis, impede and delay the assembly of the module, and represent a non-negligible expense, not only in terms of manufacture and inventory maintenance of additional components, but also in terms of assembly and installation. The mounting brackets could, under certain circumstances, e.g., if the reader is dropped and subjected to a high shock force, break loose, in which case, undesirable motion between the PCBs might result, and, in a worst case, the required predetermined angular relationship between the engine PCB and the handle PCB might not be maintained, and, as a result, reading performance could be degraded.
Accordingly, it would be desirable to avoid the use of mounting brackets, to make the reader more resistant to shock impacts, and to simplify, expedite, and reduce the cost of, assembling the module.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and locations of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The imaging module, the imaging reader, and the method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.